Purchase this article with an account.
Michael Engles, Corine Ghosn, Sveti Ugarte, Shruti Mistry, Werhner Orilla, Goodkin Margot, Mohammed Dibas, Michael R Robinson; The effects of selective laser trabeculoplasty (SLT) in normotensive beagle dogs. Invest. Ophthalmol. Vis. Sci. 2019;60(9):3796.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Selective Laser Trabeculoplasty (SLT) is a popular, non-pharmacological treatment for the reduction of intraocular pressure (IOP) in patients with ocular hypertension or open-angle glaucoma. Beagle dogs are a commonly used dog breed to evaluate the effects of topical ocular prostaglandin analogues as well as sustained release drug delivery systems. The purpose of this study was to investigate the effects of SLT in normotensive beagle dogs.
SLT using standard clinical procedures was applied unilaterally to 11 normotensive, drug-naïve beagle dogs (female, weight 7–12 kg). During SLT, adjacent, non-overlapping spots were made over 360° of the trabecular meshwork (Endpoint: “champagne bubbles”; laser energy = 0.9mJ). The procedure was divided across two sessions (180°/session) separated by 2 weeks to allow recovery. IOP was measured prior to SLT and then monitored weekly for up to 10 weeks. Data expressed as mean±SE.
Baseline IOP was 19.3±0.8 and 19.4±0.8 mmHg, in the SLT and control eyes, respectively. Post SLT, IOP at peak reduction was 14.0±1.0 and 14.2±0.9 mmHg in the SLT and control eyes, respectively. Nine out of 11 animals returned to baseline by end of study period (6-10 weeks). A responder analysis was conducted. Animals were categorized as responders (i.e., clinically relevant decrease in IOP of 3 mmHg, or ≥15% reduction) or non-responders. Six dogs were categorized as responders, four of which returned to baseline, and two continued to exhibit a >3 mmHg decrease in IOP at the end of the study. Peak decrease in IOP for responders was 7.9±1.3 and 7.5±1.2 mmHg in the SLT and control eyes, respectively. The remaining five animals were categorized as non-responders with mean peak decrease in IOP of 2.2±1.5 and 2.9±1.4 mmHg in the SLT and control eye, respectively. Six dogs had mild hyperemia that was treated with topical medication.
Beagle dogs positively responded to the SLT procedure, with a variable success rate. For 60% of the dogs tested, SLT provides a ≥15% peak reduction in IOP during the observation period of 6 to 10 weeks. Furthermore, the contralateral, naïve eye also exhibited an IOP decrease comparable to the laser treated eye. A contralateral IOP lowering effect of SLT on the fellow untreated eye has also been observed in humans. This model can be used to evaluate the safety and efficacy of combining SLT with topical or sustained-release medications.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
This PDF is available to Subscribers Only